1. Field of the Invention
The present invention relates to a multilayer ceramic electronic component including, for example, a multilayer ceramic capacitor or the like.
2. Description of the Related Art
In recent years, a multilayer ceramic capacitor (electronic component body) which is a chip-type electronic component made of ceramic has been commonly used. However, when a multilayer ceramic capacitor is directly mounted by a solder on a mounting board, the mounting board on which the multilayer ceramic capacitor is mounted and the multilayer ceramic capacitor expand or contract according to the respective coefficients of thermal expansion when the temperature changes, and the difference in coefficient of thermal expansion between these elements causes a stress that leads, for example, the damage of the multilayer ceramic capacitor or the breakage of the joint. Also, when the mounting board is liable to bend as in the case of a thin glass epoxy board, a stress similar to when the mounting board bends can occur. Further, when a force is exerted on the mounting board itself, the mounting board bends and deforms, and thus a stress can similarly occur.
Such a stress exerted on a multilayer ceramic capacitor can cause occurrence of cracking in the multilayer ceramic capacitor.
In order to solve the aforementioned problem, it has been proposed to attach a metal terminal formed of a metal plate on the external electrode of the multilayer ceramic capacitor, and a metal terminal member is soldered to the mounting board in the condition that the multilayer ceramic capacitor is lifted off the mounting board (see, for example, Japanese Patent Application Laid-Open No. 2001-189232).
According to such a method, the heat at the time of soldering propagates to the multilayer ceramic capacitor via the metal terminal, so that it is possible to prevent the thermal shock from being exerted on the multilayer ceramic capacitor. Further, even when a stress due to temperature change or deformation of the mounting board occurs, it can be advantageously absorbed by the elastic deformation of the metal terminal.
However, even when a metal terminal is provided, cracking sometimes occurs in the multilayer ceramic capacitor. As a result of diligent effort, the inventors discovered that this is caused by occurrence of a tensile (compressive) stress in a plating film formed on the surface of the metal terminal and the external electrode, and cracking occurs from the end portion of the external electrode where the stress is most concentrated toward inside the multilayer ceramic capacitor.